Error uploading attachments to a Sharepoint online list

Occasional Contributor


Does anyone have an issue (or solution) to an error message we receive when attaching files to a list? This tends to happen intermittently and happens more often with large files or multiple attachments. It either saves the list item without attachments or fails to save with the error message 'Your changes conflict with those made concurrently by another user....)

I have a SP Designer workflow running on the list but i've added a pause before it starts. I also have a calculated column on the list.

6 Replies

@Tom Hamilton

Are you exceeding the limit "The maximum size for files attached to list items is 250 MB"?


@Paul de Jong 

Hi Paul,

No, i've just tried this with a file size of 18Mb and still get the problem. I've now had reports this is happening on another list too. 

@Tom Hamilton Does it keep happening with the same (types of) files? Or will a file that fails to upload one time upload fine if you try again?

Yes, sometimes a file will fail to upload and the next time it works, I've tried it with various file types too. With the form open I can see it creates the list item before giving me the error message.

Hi @Tom Hamilton  , may i know how did you manage to solve your issue in the end? I am facing same issues too - appreciate if you can share with me. Thank you!

Hi, It has stopped happening yes. We replaced the SP Designer workflow with a Power Automate flow but I don't believe that prevented the errors. However we then added a Delay step of 2 minutes into the flow before all other steps and that seems to have worked. We've also since replaced IE with Chrome as our default browser which may have also had an effect.